Method of making leather straps



Sept. 25, 1951 P. J. SHIVELL' 7 ,7

METHOD OF MAKING LEATHER STRAPS Filed Nov. 30, 1948 2 Sheets-Sheet 1 I INVENTOR.

/Q////R J. gfiV/VEZL BY v ATTORNEYS Sept. 25, 1951 P. J. SHIVELL 2,568,770

METHOD OF MAKING LEATHER STRAPS 2 Sheets-Sheet 2 Filed Nov. 50, 1948 ywz INVENTOR. 1 0/4 0 .7. Jan 14 area, for example, the hide Ill is cut or slit along the lines II and [2 to form strips of leather l3.

Strips I6 may also be out having a lesser natural curvature satisfactory for various purposes by cutting the indicated portion of the hide along the lines 14 and I5.

As indicated in Figure 1, the cuts or suis I are substantially parallel to the longitudinal axial line of the hide whereas the slits or cuts [4 are perpendicular thereto." In eithercase, the longitudinal edges of each of the'stripslt and I6 are substantially straight and. parallel when out from a fiat hide.

In thecase of strips 13, due to characteristics of the fibrous structure of hides, those parts of said strips which are derived from portions of the hide nearer to thetline of the backbone are of greater density than those parts of the strips derived from portions of the hide more remote therefrom; and as shown in Figures 2,3, and 4, each strip I3 is of a more dense fibrous structure at its right hand edge than at its left hand edge. As shown inFigures L5 and 6 .the strips I6 are ofgreater fibrous density and are made up of shorter fibers at their, left hand. ends, that is nearer to the line of the backbone, than at their right hand or outer ends.

A leather strap l1, particularly suitable for use in forming check strapsof the. type illustrated in Patent No. 1,993,531 for example, isconveniently produced from one of said strips l3.. For this purpose, a strip [3 is subjectedto forces which cause elongation of the one side or edge portion in,relation,to the other side or edge portion thereof. As indicated;in, Figure 10, in a hand procedure, one end ,of strip I3 is secured in a clamp l8; and that portion of strip l3 adjacent to the right hand edge I 9. is elongated by tension applied in any suitable manner, for example through a clamp ZUYwhich is attached to the strap in an oblique position and subsequently pulled to rectangular relation. Thus, right hand edge portions of strip [3, as viewed in Figure 10, are elongated in relation to the left hand edge portions thereof. The result is that the right hand edge I9 assumes a convexly curved outline whereas the edge 22 assumes a concavely curved outline substantiallyparallel to that of IQ. Even if tensionis applied uniformly over the width of the strip (e. g. pivotally to the clamps l8 and/ or 20), a curvature will be developed, since the material on opposite lateral portions has different resistance to tensile stress.

In an alternative procedure the check strap, as I1,Figure '7, is produced by passing a strip I3 between positively driven rollers 23 and 24, Figures 9 and 10. Whereas theroller surface of roll 23 is in this case shown cylindrical, that of roll 24 is conical, with its greater diameter at the right side, as viewed in Figure 9, and its smaller dimension at the left hand side. Holes 25 and 26 may be punched or out near the ends for attaching bolts.

To attain elongation of edge portion 19 by means of rolls 23-24, said strip I3 is passed between said rolls with the edge l9 engaged in the relatively narrow space between said rolls and the edge 22 in the relatively wider portion of said space. In other words, the edge l9, representing a portion of less dense fibrous structure of the strip [3, is subjected to a greater compressive effect on its thickness and a greater tensile stress along its length than is applied to the more dense portion of the strip l3. This differential compression and tension, applied progressively as the strip [3 is moved between said rolls when. they are being driven, causes that edge portion [9 of said strip to be compressed and elongated in relation to edge 22 so that, in the finished product or strap I1, Figures 7 and 8, the strap is convexly curved.

The above described rolling operation may be. employed with or without the simultaneous application of tension produced by pulling on'a portion of the strip in ,adirectionindicated bythe arrow, for example by means such asthose shown in Figurepll, orother suitable means including pulling by hand.

Althoughthe1steps ,of procedure, above de-.

scribed are applied to strips, as, l3, it is contemplated that a leather band product similar in its curvature to the strap ,-l! and useful for similar purposes'may be obtained by similarly processin strips which have been ,cut from the hide .on linesoblique or perpendicular to the axial line of the backbone region thereof, provided that the areaof each stripis a portion of the hide which was distorted laterally when thehide was.

flattened from the shape ithad. onthe animal.

Such stripscut perpendicular are shown at I6.

In this case, the elongated edge or lateral area of the strip should be that toward a line perpendicular to the longitudinal axis ofi-the hide at a point approximately midway between the shoulder and the base of the tail. The shorter relatively: less stretched. part will be at the fore edge or the rear edge according to the side of the perpendicular line from which it came, thus taking advantage-of the natural curvature of the hide which has been pressed out during tanning and other treatments but I have found to be still latent inthe strips. Stated in another way, the

part or the hide: included in the strip I3. or IE or, the like, when onthe animal had a threedimensionalcurvature with its center of curvature displaced laterally from'the' area included in the strip; and'advantageously from .a mid-part of the strip length. The application, of pressure and/or tension along one edge or lateral portion' effects an elongation, of that portion in relation to the opposite edge and ,will'release such latent curvature, and, produce a strap of arc-shaped form not dissimilar in'appearance to that shown .in Figure 7.; j.

It will be apparent from the foregoing description and from Figures 9, 10, and 11 that-the curvature 'can..be controlled 'by'the amount. of pressureand/or "tension, fwhich can be varied, .not only; as ,to any desiredportion of the strip but also from one portionto another. For example as indicated in Figure 11, by changing the angular relation of clamps l8 and 20, or by 'engaging-a greater or less width from the edge tension'may-be applied to a greater or less width of the strip. vI fthe clamps l8 and 20 are not at fixed angular relation, but are pivotally mounted, the resulting strap will have itslatent curva-- ture morefully developed, and allacross its width will have about the same resistance to stretchr I:

Also, all or any desired edge portion of the strip I3 can be subjected to the compressing action of rolls 23 and 24 and/or to tension by device as shown, or by other suitable means.

In processing strips [3 or l6 by combined action of pressure rolls, and direct pull, the attendant tension exerted lengthwise of the strip by the operator serves to control, in part, the degree of curvature of the are produced. The degree of differential stretch produced by the rolls depends upon the conical form of one or both of the rolls 23, 24 and the differential compression by the angular relation of their faces. Each of these contributes to a certain extent to the curvature given the product strap. These effects of the rolls may be varied to meet different conditions. Thus, by regulating and controlling the amount and location of tension and/or compression the method of the present invention enables the operator to control the degree of arc produced upon the initially straight edge strips I3 and is within limits, of course, imposed by the structural character of the strips. Thus the strip is given the desired curvature to form a truncated conical loop; and, if the maximum stretch is along the side in which the leather has been more compressed or less stretched in its prior treatment, its latent curvature is developed and all parts of the strip are brought more nearly into balance with respect to resistance to stretch in a truncated conical loop. v

A leather strap derived from the sources and processed as above described presents a product of arc shape produced by readjustment or redistribution of the natural fiber as distinguished from one produced by initially cutting the leather to are shape. This results in a more uniformly strong and durable piece of leather which when used as a check strap adjusts itself to a given picker stick snubbing application more effectively and wears substantially longer in that use than is the case with known forms of straps. In addition to advantageous performance, the above described product enables the manufacturer to cut more straps from the same area of leather than would be possible if the straps were cut initially in arc form and is therefore more economical than known products for a similar purpose.

Various embodiments may be made of the above invention andchan'ges might be made in the embodiments and examples of procedure above set forth. It will also be apparent from the foregoing that a leather strap made in accordance with the method hereinabove described is well adapted to attainthe ends and objects hereinbefore set forth and to be economically manufactured since both the article and the method of making it are suited to usual production methods and are susceptible to a substantial latitude of variations as may be desirable in adapting the invention to different applications.

I claim:

1. Method of making a leather strip which includes the steps of cutting hide leather material from the region of the back, upper belly and hind quarters along lines substantially parallel to the central longitudinal axial line of the backbone region of the hide to form a leather strip, applying pressure and tension simultaneously thereto in a direction to stretch that portion of said strip which was more remote from said longitudinal axial line of the hide more than the less remote portion.

2. Method of making a leather strip which includes the steps of cutting hide leather material from the region of the back, upper belly and hind quarters along lines substantially parallel to the central longitudinal axial line of the backbone region of the hide to form a leather strip and applying differential pressure over the width of the strip to elongate that portion of said strip which was more remote from said longitudinal axial line more than that which was closer.

3. Method of making a leather strip which includes the steps of cutting hide leather material from the region of the back, upper belly and hind quarters along lines substantially parallel to the central longitudinal axial line of the backbone region of the hide to form a leather strip and applying differential pressure over the width of the strip greater in that portion which was more remote from said longitudinal axial line than in that which was closer and progressively lengthwise of said strip.

4. Method of making a leather strip which includes the steps of cutting a strip from a previously flattened tanned hide and from a portion thereof, which, when on the animal, had substantial three-dimensional curvature, said cutting being along lines transverse to the direction of lateral distortion of the tanned hide when flattened from said three-dimensional curvature, and subjecting said strip to rolling contact pressure across its area in a direction to develop the latent curvature in the strip by relieving the stress imposed inflattening the hide and thereby to lengthen one edge of the strip in relation to the other.

5. Method of making a leather strip which includes the steps of cutting a strip of hide leather material which has greater fibrous density at one edge and less fibrous density at the other, and subjecting said strip rolling contact compression which varies progressively transversely across said strip being greater along the edge of less fibrous density.

6. Method of making a leather strip which includes the steps of slitting hide leather material to form a strip and applying a compressive force in the direction of its thickness while subjecting said strip to tension longitudinally thereof. said compressive and tension effects being greater at one lateral edge than at the opposite lateral edge thereof.

PHILIP J. SHIVELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,019,396 Williams Mar. 5, 1912 1,241,087 Brogan Sept. 25, 1917 FOREIGN PATENTS Number Country Date 11,481 Great Britain of 1899 

